Gearcarapace — a clockwork beetle minted from a rappter genome
A brass clockwork beetle whose shell breathes open over a gear train that actually meshes.
What this is
Gearcarapace is a completely new creature — a clockwork beetle — with its own model and its own animation, hatched fresh every time from a real .egg "rappter" genome. It is not a re-skin of the stock holographic blob. Model: A clockwork beetle whose brass elytra split along a breathing seam to reveal a real, conjugate-meshed gear train (module-matched teeth, tangent centers) running its spine — plus articulated 2-segment legs, serrated mandibles, segmented antennae, and glowing eyes, all built deterministically from the genome id.
Press New Gearcarapace and a brand-new, unique genome is minted, hashed to a 12-character id, and rendered live. Press Save .egg to download the real cartridge — the same .egg format the OpenRappter ecosystem hatches — or Load .egg to bring one back byte-exact.
How it moves
The gear train is physically correct: adjacent gears counter-rotate at the exact N0/N1 tooth ratio (verified numerically), computed via a conjugate-mesh chain that re-derives every downstream gear's angle from the drive gear each frame so meshing can never drift. The mandibles clack and the eyes pulse off the actual head-gear rotation (a cam), the shell seam breathes open to expose more of the train, and legs twitch in time with the rpm.
The genome behind it
Every Gearcarapace is packed as a genuine rappter .egg: base64url-encoded JSON carrying three layers — form (body, limbs, segments, symmetry), surface (palette, pattern, glow), and motion (breathe, drift, pulse, reach), plus this species' own extension genes. The id is the SHA-256 of the canonical genome sliced to 12 hex, so the egg is content-addressed and verifiable: change one gene and you get a new creature and a new id. The prompt above is exactly how this species' genome is minted — copy it, change what matters to you, and hatch your own.
Prompt
Mint a Gearcarapace: a clockwork mechanical beetle. Form is bilateral, shape biased to 'ring', with segments (4-10) becoming the count of spine gears — alternate large/small tooth counts (16-22 / 10-13) at a constant module so tangent gears mesh, and set limbs to 4-8 legs. Surface picks a metal family (brass-weighted, occasionally copper/steel/gunmetal/rare gold) that resolves to a [dark, mid, light, glow] palette, with stripe or glow patterning, glow 0.35-0.92 and a touch of patina. Motion is machine-driven: pulse (0.4-1.0) sets the drive-gear rpm (6-52) that every counter-rotating gear derives from, breathe opens the elytra seam, reach twitches the legs, and clack drives the mandibles off the head gear. Every field hashes into the egg id, so each mint is unique yet fully reproducible on load.Paste this into Claude, Cursor, or Copilot. Change one thing that matters to you.
What I learned shipping it
- Deriving each gear's angle from the drive gear via a conjugate-mesh formula (rather than integrating per-gear velocities) guarantees perfect meshing every frame with zero accumulated error
- Bare `FAUNA.frame++` inside the loop relied on window being the global — using `window.FAUNA.frame++` is unambiguous and was the one real bug the render-path test caught
- Node + vm with a recording 2D-context mock exercises the entire draw path (150 frames + New + Load) and proves zero runtime errors without a real browser
- Verifying the load-bearing physics numerically (counter-rotation sign + exact N0/N1 ratio per pair) is stronger evidence than eyeballing the animation